1. Field of the Invention
The present invention relates to a header for a heat exchanger, and more particularly to a header constructed as a tank structure from at least two members joined to each other.
2. Description of the Related Art
A structure of a header for heat exchangers formed from two members is known, for example, as disclosed in Japanese Utility Model Laid-Open HEI 3-121375. In this structure, as shown in FIG. 8, a pair of curved members 101 and 102 are joined to each other to form a barrel 103 of a header 104. Free end portions 102a of member 102 are offset outwardly, and the inner surfaces of free end portions 102a and the outer surfaces of the end portions of member 101 are joined to each other. A cap 105 is provided, so that the cap 105 seals each open end of the formed barrel 103 from the exterior.
In such a structure, because free end portions 102a of member 102 are offset outwardly, protruding portions are formed on the outer surface of the barrel 103. Therefore, the inner surface of cap 105 is formed in a shape conforming to the exterior shape of barrel 103 including the protruding portions, and the shape of the inner surface of cap 105 and the structure of the cap 105 itself are complicated.